Process of depilating and rating hides and a bate for these purposes



rnocsss o mus AND POSES Em Wslierstein, New York,

muller, Stspleton, N. Y to stein Compsny, End, New York. N. E, e

j rstion of New York No Drawing. Applicationmy 25, 1982,

' 818,546. Renewed June h,

12 "ens-ms.

In order to brim the cured or otherwise preserved. m skins or hides to a condition closely approxieting the'nstmsl state they are subjected to a,

process, that is, this soaking process 'eflec wftening of the skin. This is usually carried out by washing and permitting theskinsto liein 3 water, wither without the addition of certain chemical or enzymatic for varying Hmesssfromsfewhourstoefewdnve.

After the hides or skins have been soaked to the desired extent, the hides are treated so that they 20 csnbe dehaired, the hairoi'thehidesbeinslow ened so that it can be easily removed by various dehsiring methods. The process commonly used for loosening the'hair consists in soaking the owns or hides in lime solutions or lime solutions 25 to which sulfides, such a sodium sulfide, led

arsenic or other chemicals have been added. It has also been proposed to effect the loosening of Y thehsir of the hides or skins by certain enzymatic, methods, such use of enzymes being usually car-- so ried out after the skins have been first subjected to what is known as an alkaline bath. After the hides or skins have been subjected'to the lime or alkaline process, they are usually partly neutralized and then subjected to s bsting or pwering as process.

\ In carrying out this particular method of buting, the hides or skins are neutralized to a. pH was from a slight acidity to about 10, and this lessening of the alkalinity is achieved by the 40 addition of s suitable scid,suitable ecid salts or ammonia salts, and neutralizing agents may also be -formed by a bacterial action, as, for instance,

by the fonnetion or production of lactic, acetic or butyric acids.

to Eating baths have been suggested containing proteolytic enzymes which act on certain of the constituents of the hides .or smns, The enzymes or enzymatic products used for this bsting bath m be derived from various sources, as, for in-= 5d stance, from pancreas glands or. from preparations which contain the proteases of various plants or molds, or other micro-organisms. es, for instsnce', bacterial pmtesms.

This batlng or pueringprocess, to which the 59 mm are subjected, isused tosoiten the'hidu BATE roe.

oss (oi. lie-er end get the hides in proper condition for tanning so that the resulting leatheris of the desired quality. Where the skins or hides are dehsired by the use of proteolyticenwmes, the special bstinig mthods above referred to are not as a rule neces- 5 sexy, the hating or conditioning of the hidw or smns W place'simultaneously with the loosening of the heir, so that when the hide is dehaired it hw also been suitably bated or softened, and this method of dehairing and hating may be car- 10 ried out at the some time and in the same beth. Whatever the process employed, however, the" hides or shins sfter the dehairing and batting orv puerins should have s soft or flaccid feel and. should be sumciently soft so that; as a rough test,they will retain the impression of s. thumb print, the softness depending upon the kind of finished leather desired, and the hides and skins should have s clean and low grain, by which is meant the pores of the skins should be as fine as msible and flattened out so that the grain feels very smooth; inother words, the grain should be the opposite of what is how as a "goose flesh eflect.

It is very desirable, if not msentiel, that in the production of s finished leather having the dwred fineness or tightness of the grain that thisv condition of'the hide or sun should be produced prior to the tanning process, that is, during the dehairing end hating processes. We have discovered that the desired grain condition and consequent improvement in the finished leather can be obtained by treating the hides and skins, during the above mentioned methods or any of them, with comparatively small amounts of water soluble organic substances which have intheir chemical constitution the group represented by the general formula I ten thst is, the -'-1 -'----i group, for instance, such substances as scetemide, ures, semi-carbazide, salts of csrbs'minic scid, biuret or other derivetives of substances wherein, in the group,

'amido compound is most eilfectively obtained when the compound is utilized in very small quantities usually less than 1% in the bath.

- The amounts of these substances needed for the above described purpose are relatively small and can be varied greatly, depending on the effect desired. As a general rule, 1 part-in200 to 1 part in 1000 parts of the bath in which the skins are treated will be sufiicient to give good eifects.

" These substances may be applied either in a separate bath at any-of the above mentioned stages prior to tanning, or by adding these substances in the proper proportions to a bath which is used in the above processes. For instance, these substances can be used by adding the same during the soaking process, or the skins after the soaking process may be treated in a bath containing the above mentioned substances. The skins may also be subjected to accomplish the purpose of this invention after they'have been subjected to the lime or lime and sulfide dehairing bath.

We have found that a very good method and one which has given excellent results is the one in which we use these substances in. connection with the hating process, or in case the hides are dehaired with an enzymatic unhairing process, by adding same to the enzymatic dehairins bath. Substantially the same results are obtained by using a separate bath subsequent to the hating or enzymatic dehairing and using'a bath which contains any or a mixture of the above mentioned substances in the proper proportions.

The action of these substances is particularly pronounced on the condition of the grain of the hide or skin. We have found that by treating the hides or skins asset forth the grain becomes smoother, tighter, and the appearance of the finished leather is far superior and of better quality than of leather which is finished and tanned in which the treatmentwith these substances has been omitted. For certain kinds of leather, for instance, in thetreatment of heavy hide, as in the manufacture of sole leather, we

have found that proteolytic enzymes for hating or puering may be greatly reduced or even dispensed with entirely when using a bath-containing the above substances. As a general rule, however, we-have found that by combining the good effect of the. above mentioned substances together with a proper hating, such as is done by means of proteolyticenzymes, the best results are obtained. For such a procedure it is advisable, as mentioned above, to use these substances in the same bath with the proteolytlc enzyme bath or at a stage shortly before or shortly subsequent to the hating process. Many substances belonging to the above mentioned groups and suitable for the purpose of the invention are now available in technical pureform, for instance, urea or acetanilide.

As examples oi carrying out our invention, the following may be given:'

Example No. 1.--'1000 lbs. calf skins are soaked and then unhaired as it is usually done, by means of a lime bath containing sodium sulfide. The

are washed and then-brought into a bath containingdtoo to 2000 parts water are washed and brought into a bath containing and left therein for a few hours, or if more de sirable, overnight, in which case it is preferable to add a suitable disinfectant. After this treatment, the skins may be subjected to a desired hating treatment and are finished as desired. 5 Example No. 2.1000 lbs. dry goat skins are soaked, limed and unhaired as usual. They are partially neutralized and hated in a bath containing a proteolytic enzymatic bating preparation, such as a pancreas preparation, or an enzyme preparation of bacterial origin. To this hating hath there are added. $5 to 2 lbs. of acetanilide or urea for each 1000 lbs. of bating liquor. The hating is carried out as desired, and the skins finished in any desired way. 15

Example No. 3.--1000 lbs. dry weight goat skins are soaked and unhaired in the customary lime bath. They then are puered in the usual way with a dog dung infusion. After the puering they from 1 to 5 parts of urea or. acetamide or a mixture of both in 1000 parts of water and left therein for a sufiicient time, for instance, a few hours or overnight. If the time is longer than a few hours, the addition of a disinfectant is recom- 25 mended.

hath containing caustic soda. After this the skins are partly neutralized and subjected to the influence of an enzymatic dehairing bath containing proteases' of bacterial origin. A disinfectant is added to this dehairing bath; 10 parts urea are added for 5000 parts of the dehairing bath. After the dehairing, the skins are tanned and finished as desired.

EzampleNo. 5.1000 lbs. goat skins are soaked as usual and subjected to an alkaline bath containing caustic soda. After the skins are partly neutralized they are subjected to a dehairlng bath produced by the addition of an enzymatic liquor of bacterial origin to which a disinfectant has been added. After the hair has been loosened and theskins have been unhaired, they are left in this bath long enough until the grain has been brought into the required condition; as a rule a few hours issufiicient time. They are then finished as usual. v

Example No. 6.-Sheep skins are painted on the flesh side with a preparation containing dehairing enzymes of bacterial origin. To these preparations, approximately 1% by weight of acetamide are added. After dewooling, the skins are finished in the usual way. Of course, the amount of acetamide added for this purpose may vary in a wide range and instead of acetamide' any other substances of the above mentioned groups can be used.

In all the above examples the final leather will be of better quality and-will especially show a finer and tighter grain than if the treatment said substance utilized in the amount of. not more than 1%;by weight in a non-putreiac- ,bating the hides or skins prior to tanning in a 5.Thepmcessc!treatinghidesand 5 Inert substances such as 'wood flour or infusorial earth .Ecample B.A mixture containing:

Pounds Urea 20 Acetanilide 10 Ammonium chloride 60 Dried pancreas gland 1-10 'Inert substances such as wood flour or intusorial earth; l-i0 Instead of the U. S. P. pancreatin as in Example A, a corresponding amount 01 pancreas gland or pancreas extract may be used, or a protease preparation may be employed, such as teases of bacterial origin, which are of required strength While a filler is preferably used as-given in the examples, this may be omitted if desired.

. It will also be understood that instead of ammonium chloride, as given in Example B,.other deliming agents such as sodium bi-sulflte, ammoniumsuliate, boric acid, or mixtures 01 these substances may be employed.

While the invention has been described in its preferred form, and in accordance with the best practice now known to us, it will be understood that the invention is not to be limited precisely tothisandmaybevariedinsomeparticulsrs and that the examples given are merely illustrative.

What is claimed is:

1. A process 0! treating hides and shnsto produce an improved leather, which consists in hating the hides or-skins prior to in a bath containinga proteolytic enzymatic preparation and organic substances having the group tive medium. I 2. A process or treating hidesand skins to produce an improved leather, which in 4. Aproces'soitreatinghidesandskinstoproduce an improved leather, which. consists in treating the hides or skins prior to tanning in a bath containing a relatively small uof -acetsnilide and urea.

is produced by the cultivation of molds, or pro- "and a 'deliming agent,

being utilized in amounts less than 1% by weight produce an improved leather, which consists in treatingthehidesandskinspriortotanninginabatingbathcontaining organic w. having the group t\ wherein one or both hydrogensare substituted by an alkyl orphenyl group.

6. The process ol -treating hides and skins to produce ,an' improved leather, which consistsin subjecting them to a bath-contamlng'a proteolytic subjecting them to a bath containing a pro-- teolytic enzyme and a substance having the wherein one or both hydrogens are by an alkyl or phenyl group. v

8. A bate preparation containing organic substances having the group 1 and a proteolytic' enzyme, said organic substances being utilized in amounts'less than 1% by weight in a non-putreiactive medium.

9. A hating preparation containing organic substances having the group 7.

NH: said organic substances in a non-putrefactive medium.

10. A bate preparation containing organic substances having the group a proteolytic enzyme, and deliming agents, said organic substa being utilized in amounts less gen 1% by weight in a non-putreiactive meum.

11. A hating preparation containing'urea, and a protease, said preparation being utilized in a bathdevoid of complex organic mixtures which give rise to putreiaction.

12. A hating preparation con i protease, and an ammonium salt, sai pation being utilized in a bath devoid of com 

